Refund claims procedure: file within prescribed time with proof and quantification, subject to unjust enrichment rules. Claims for refund of excise duty must be filed in duplicate with the jurisdictional Assistant/Deputy Commissioner within one year from the relevant date, usually the date of payment, with grounds, payment proof, a quantification worksheet and supporting documents. Refunds from pre deposits under appeal, payments under protest, quasi judicial or court orders are exempt from the one year limit. Refunds require proof that the duty incidence was not passed on; otherwise amounts are credited to the Consumer Welfare Fund. The sanctioning authority must issue a show cause notice and hear the claimant before rejecting claims; high value claims undergo pre audit while others are post audited, and complete claims should be disposed within three months.